The Secretary established the health endangerment determination for the class of
employees covered by this report based upon the findings summarized below.

(1) Pursuant to 42 C.F.R. § 83.13(c)(3), NIOSH established that there is a reasonable
likelihood that such radiation doses may have endangered the health of members
of the class. Pursuant to 42 C.F.R. § 83.13(c)(3)(ii), NIOSH specified a minimum
duration of employment to satisfy this health endangerment criterion as “having
been employed for a number of work days aggregating at least 250 work days
within the parameters established for this class or in combination with work days
within the parameters (excluding aggregate work day requirements) established
for one or more other classes of employees in the Cohort.”

(2) NIOSH did not identify any evidence from the petitioners or from other resources
that would establish that the class was exposed to radiation during a discrete
incident likely to have involved exceptionally high-level exposures, such as a
nuclear criticality incident, as defined under 42 C.F.R. § 83.13(c)(3)(i).

(3) The Board concurred with NIOSH’s finding that the health of the class may have
been endangered and defined the class according to the 250-workday requirement
specified under 42 C.F.R. § 83.13(c)(3)(ii).

Vv. — Effect and Effective Date of Designation

The Secretary submits this report on the designation of one additional class to the
SEC for review by Congress, pursuant to 42 U.S.C. §§ 7384/(14)(C)(ii) and
7384q(c)(2)(A), as amended by the Ronald W. Reagan National Defense
Authorization Act for Fiscal Year 2005, Pub. L. No. 108-375 (codified as amended in
scattered sections of 42 U.S.C.). Pursuant to 42 U.S.C. § 7384/(14)(C)(ii), as
amended by the Ronald W. Reagan National Defense Authorization Act for Fiscal
Year 2005, Pub. L. No. 108-375 (codified as amended in scattered sections of 42
U.S.C.), the designation in this report will become effective 30 days after the date of
this report’s submission to Congress “unless Congress otherwise provides.”

VI. Administrative Review of Designation

The health endangerment determination of the designation provided in this report
may be subject to an administrative review within HHS, pursuant to 42 C.F.R. §
83.18(a). On the basis of such a review, if the Secretary decides to expand the class
of employees covered by this designation, the Secretary would transmit a
supplementary report to Congress providing the expanded employee class definition
and the criteria and findings on which the decision was based.

HHS Special Exposure Cohort Designation:
Horizons, Inc.


HHS Designation of Additional Members of the

Special Exposure Cohort
under the
Energy Employees Occupational Illness Compensation Program Act of 2000

Designating a Class of Employees from

Horizons, Inc.
Cleveland, Ohio

HHS Special Exposure Cohort Designation:
Horizons, Inc.


L Designation

I, Michael O. Leavitt, Secretary of Health and Human Services (Secretary), designate
the class of employees defined in Section II of this report for addition to the Special
Exposure Cohort (SEC), as authorized under the Energy Employees Occupational
[liness Compensation Program Act of 2000 (EEOICPA), 42 U.S.C. § 7384q.

MAY 8 0 2008 se

( S

Date Michael O. Leavitt

ll. | Employee Class Definition

All Atomic Weapons Employer (AWE) employees who worked at the
Horizons, Inc. facility from January 1, 1952, through December 31, 1956,
for a number of work days aggregating at least 250 work days occurring
either solely under this employment or in combination with work days
within the parameters established for one or more other classes of
employees in the Special Exposure Cohort.

Ill. Designation Criteria and Recommendations

Pursuant to 42 U.S.C. § 7384q, for the class defined in Section II of this report, the
Secretary has determined, and the Advisory Board on Radiation and Worker Health
(Board) has recommended, that
(1) it is not feasible to estimate with sufficient accuracy the radiation dose that the
class received; and
(2) there is a reasonable likelihood that such radiation dose may have endangered
the health of members of the class.

The SEC final rule states in 42 C.F.R. § 83.13(c)(1) that it is feasible in two situations
to estimate the radiation dose that the class received with sufficient accuracy. First,
the rule states that radiation doses may be estimated with sufficient accuracy if
NIOSH has established that it has access to sufficient information to estimate the
maximum radiation dose for every type of cancer for which radiation doses are
reconstructed that could have been incurred under plausible circumstances by any
member of the class. Alternatively, radiation doses may be estimated with sufficient
accuracy if NIOSH has established that it has access to sufficient information to
estimate the radiation doses of members of the class more precisely than a maximum
dose estimate.

The Board, pursuant to 42 U.S.C. § 73844, advised the Secretary to designate the
class as an addition to the SEC in a letter received by the Secretary on May 2, 2008.

HHS Special Exposure Cohort Designation:
Horizons, Inc.


IV. Designation Findings

Feasibility of Estimating Radiation Doses with Sufficient Accuracy

The Secretary established the feasibility determination for the class of employees
covered by this report based upon the findings summarized below.

(1) The principal sources of internal radiation doses were exposures to thorium (as
well as thorium daughter products and thoron), uranium, and radioactive silver.

(2) NIOSH did not find any bioassay monitoring, urine sampling, or whole-body
counting data. The only available internal monitoring data are from periodic air
monitoring. Air samples and wipe samples were taken and analyzed for (alpha)
thorium and reported in December 1954 and again for September 1955. Limited
uranium air samples were also taken and reported for July 1953.

(3) The principal sources of external radiation doses were exposures to thorium,
uranium, and radioactive silver. NIOSH has access to the original external
dosimetry information and documentation for the period from 1954 through 1955,
although some gaps in data do exist. NIOSH has source term information for the
thorium, uranium, and silver process activities. The original external dosimetry
data provide actual doses recorded by individuals for a specific time period.
NIOSH has identified recorded external doses for most of the individuals.

(4) For the workers in the designated class, NIOSH found that the available
monitoring records, process descriptions, and source term data are not sufficient
to reconstruct radiation dose.

(5) Pursuant to 42 C.F.R. § 83.13(c)(1), NIOSH determined that there is insufficient
information to either: (1) estimate the maximum radiation dose, for every type of
cancer for which radiation doses are reconstructed, that could have been incurred
under plausible circumstances by any member of the class; or (2) estimate the
radiation doses of members of the class more precisely than a maximum dose
estimate.

(6) The Board concurred with the NIOSH evaluation and recommended the proposed
class for addition to the SEC.

(7) Although NIOSH found that it is not possible to completely reconstruct radiation
doses for these employees, NIOSH can reconstruct occupational medical dose
and all external dose. Therefore, individuals with non-presumptive cancers may
be considered for partial dose reconstructions.

Health Endangerment

HHS Special Exposure Cohort Designation:
Horizons, Inc.